This invention relates to a graft anchor for securing a graft in a bone tunnel.
A torn ligament is a common injury. One way to treat the injury is to replace the ligament with a soft tissue or synthetic graft, formed from a ligament or tendon tissue or synthetic material. A surgeon drills a tunnel in the bone, and positions one end of the graft in the tunnel. An interference screw is positioned in the tunnel adjacent the graft to urge the graft against the wall of the tunnel.
According to one aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member having a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel distal of an interference member with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member has an engaging surface for engaging a distal end of the interference member to limit movement of the graft relative to the interference member.
Embodiments of this aspect of the invention may include one or more of the following features.
The engaging surface is an end face of the anchoring member. The end face has a coupling member configured to interface with the interference member. The coupling member is a protruding nib sized to fit within an opening in an end of the interference member. The nib is located in a center portion of the anchoring member. Alternatively, the nib is located off-center of the anchoring member.
The graft supporting surface is constructed to receive a graft looped around the anchoring member, and is formed by an exterior surface of the anchoring member. The anchoring member is a generally planar structure including four sides, a top face, and a bottom face forming the engaging surface. The graft supporting surface includes at least one of the four sides and the top face. The top face is indented. The four sides are flat.
The graft supporting surface includes a first indented surface defined by a first side of the anchoring member, a second indented surface defined by a second opposing side of the anchoring member, a third indented surface defined by a third side of the anchoring member, and a fourth indented surface defined by a fourth side of the anchoring member. Alternatively, the third and fourth sides of the anchoring member are not part of the graft supporting surface, and are convex surfaces.
The anchoring member defines a bore for receiving a guide wire. The bore is located in the center of the anchoring member. Alternatively, the bore is located off-center. The nib is located circumferentially about the bore.
In another aspect, an anchoring member for securing a graft in a bone tunnel includes a generally planar structure having a first side, an opposing second side, a distal end, and a proximal end face. The first side defining a first indentation for receiving the graft and the second side defines a second indentation for receiving the graft. The end face includes a protruding nib configured to fit within an opening in an end of an interference member. The structure defines a bore for receiving a guide wire. The anchoring member is configured to be positioned within the bone tunnel distal of an interference member with the protruding nib interfacing with the interference member and with the graft looped around the distal end of the structure and retained in the first and second indentations. The anchoring member limits movement of the graft relative to the interference member.
According to another aspect, the invention features a method for securing a graft in a bone tunnel. The method includes providing an anchoring member having a graft supporting surface; looping the graft over the anchoring member so that the graft is retained by the graft supporting surface; inserting the anchoring member and graft into the bone tunnel; and inserting an interference member into the bone tunnel adjacent the graft and proximal of the anchoring member so that the anchoring member engages a distal end of the interference member to limit movement of the graft relative to the interference member.
Embodiments of this aspect of the invention may include one or more of the following features.
The anchoring member is loaded onto a guide wire. Inserting the anchoring member includes inserting the anchoring member and graft into the bone tunnel with the guide wire. The anchoring member is loaded onto a distal end of the guide wire such that the anchoring member abuts a ledge defined by the guide wire. The ledge limits proximal movement of the anchoring member relative to the guide wire.
Inserting the interference member, e.g., an interference screw, into the bone tunnel includes distally advancing the interference member over a guide wire, and abutting the distal end of the interference member against an end face of the anchoring member. The end face includes a protruding nib and an end of the interference member is placed over the nib.
According to another aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member, an interference member, and a guide wire. The anchoring member has a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member defines a first bore of a first diameter. The interference member defines a second bore of a second diameter larger than the first diameter. The guide wire has a first region and a second region of a different diameter than the first region. The first and second regions of the guide wire define a shelf therebetween. The diameter of the second region of the guide wire is larger than the diameter of the first bore. The first region is insertable into the first bore with the shelf abutting the anchoring member and the interference member is insertable over the guide wire to abut the anchoring member.
Embodiments of this aspect of the invention may include a guide wire having locating mark for indicating the position of the interference member within the bone tunnel.
According to another aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member and a guide wire. The anchoring member has a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member defines a bore. The guide wire includes a first region and a second region of a different diameter than the first region. The first and second regions of the guide wire define a shelf therebetween. The diameter of the second region is larger than a diameter of the bore. The first region is insertable into the bore with the shelf abutting the anchoring member.
Among other advantages, the invention is easy to use and provides a reliable way of avoiding the graft from slipping between the interference screw and the side of the bone hole. As a result, the invention helps assure that the graft will remain securely in place even when tension is applied to it. Because the graft is directly retained by the graft supporting surface of the anchoring member, there is no need to take more elaborate measures (such as attempting to retain the graft with suture) to help prevent the graft from slipping. Furthermore, the surgeon can properly position the interference member in the bone relative to the anchoring member by simply using markings on the guide wire.